1. Field of the Invention
The present invention relates to a method for forming a film pattern by using a droplet discharge method typified by an ink-jet method, and a method for manufacturing a semiconductor device.
2. Description of the Related Art
A so-called active matrix drive display panel including a semiconductor element typified by a thin film transistor (hereinafter, also referred to as a “TFT”) over a glass substrate, or a semiconductor integrated circuit is manufactured by patterning various thin films according to a light exposure step using a photomask (hereinafter, referred to as a photolithography step).
In the photolithography step, a resist pattern is formed by applying a resist to an entire surface of a substrate, prebaking, irradiating with ultraviolet light or the like with a photomask therebetween, and then developing. Then, a film pattern is formed by etching and removing a thin film (a film formed of a semiconductor material, an insulating material, or a conductive material) in a portion not to be a film pattern using the resist pattern as a mask pattern to perform patterning on the thin film.
Reference 1 discloses a technique for forming a film over a semiconductor wafer by using an apparatus which can continuously discharge a resist from a nozzle to be a linear shape with a fine diameter in order to reduce the loss of a material required for film formation (Reference 1: Japanese Patent Laid-Open No. 2000-188251).
However, a conventional step of forming a film pattern using a photolithography step has a problem of reducing throughput due to a number of steps of forming a mask pattern, as well as wasting most of the material of a film pattern and a resist.
A photolithography apparatus used for the photolithography step has difficulty in performing light exposure treatment on a large-sized substrate at a time. Therefore, a method for manufacturing a semiconductor device using a large-sized substrate has a problem of needing to perform light exposure plural times and generating unconformity among adjacent patterns, thereby reducing a yield.
It is necessary to discharge a solution with a small droplet diameter in order to form a minute semiconductor element which occupies small area by a droplet discharge method. A diameter of a discharge opening is made small for this purpose. However, in that case, a composition of a discharge solution may be attached to the discharge opening, dried, and solidified; accordingly, a clogged opening or the like may be caused. Thus, it is difficult to continuously and stably discharge a certain amount of discharge solution. Consequently, there is a problem of causing a decrease in a throughput or a yield of a semiconductor device formed with the semiconductor element.